The migration of Be in monocrystalline samples was studied, at temperatures of between 583 and 800K, by using sputter-sectioning and secondary ion mass spectroscopy techniques. It was found that the diffusivity (table 39) obeyed an Arrhenius-type equation. The results could be described in terms of an electrostatic model for impurity diffusion in noble metals, assuming that the Be behaved like a divalent metal. A slight curvature of the Arrhenius plot was attributed to a contribution which was made by divacancies.

A.Almazouzi, M.P.Macht, V.Naundorf, G.Neumann: Physica Status Solidi A, 1992, 133[2], 305-15

 

 

 

Table 39

Diffusivity of Be in Cu Crystals

 

Temperature (K)

Annealing Ambient

D (m2/s)

583

vacuum

3.00 x 10-22

597

vacuum

6.97 x 10-22

603

vacuum

9.36 x 10-22

605

vacuum

1.00 x 10-21

615

vacuum

2.28 x 10-21

642

vacuum

1.21 x 10-20

651

Ar/H2

1.56 x 10-20

654

Ar/H2

2.13 x 10-20

654

vacuum

1.80 x 10-20

655

vacuum

2.27 x 10-20

682

vacuum

6.07 x 10-20

702

vacuum

1.70 x 10-19

705

Ar/H2

1.73 x 10-19

718

Ar/H2

3.93 x 10-19

730

vacuum

7.05 x 10-19

730

vacuum

6.82 x 10-19

751

Ar/H2

1.50 x 10-18

774

Ar/H2

5.00 x 10-18

800

Ar/H2

1.30 x 10-17